Modern PLDs include a relatively large number of pass transistors. The pass transistors may reside in a variety of PLD circuits, such as MUXs used in various PLD blocks. The pass transistors typically transmit a signal from one of their terminals (say, the source) to another terminal (say, the drain) in response to a control signal (e.g., a voltage applied to the gate terminal). Because of technological advances in device fabrication techniques, device features have shrunk in size (sometimes referred to as “technology scaling”). As a related phenomenon, supply voltages have decreased (also known as “voltage scaling”).
Threshold voltages of the transistors, however, have failed to scale in a proportionate manner. In other words, threshold voltages have decreased, although at a slower rate or pace. Consequently, the performance of the pass transistors has tended to suffer, especially in the second stages of MUXs, as the threshold voltages preclude a high-enough drive-current capability, given the supply voltage levels typically available. A need therefore exists for improving the performance of PLDs or portions of PLDs, such as pass transistors used in MUXs or other circuitry.